The accumulation of deposits on the intake valves of internal combustion engines presents a variety of problems in today's engines. The accumulation of such deposits is characterized by overall poor driveability including hard starting, stalls, and stumbles during acceleration and rough engine idle.
Many additives are known which can be added to hydrocarbon fuels to prevent or reduce deposit formation, or remove or modify formed deposits, in the combustion chamber and on adjacent surfaces such as intake valves, ports, and spark plugs. Continued improvements in the design of internal combustion engines, e.g., fuel injection and carburetor engines, bring changes to the environment of such engines thereby creating a continuing need for new additives to control the problem of inlet system deposits and to improve driveability which can be related to deposits.
It would be an advantage to have fuel compositions which would reduce the formation of deposits and modify existing deposits that are related to octane requirement increase and poor driveability in modern engines which burn hydrocarbon fuels.